Estou tentando instalar o VirtualBox 5.1
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package virtualbox-5.1 is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
W: Target Packages (main/binary-amd64/Packages) is configured multiple times in /etc/apt/sources.list.d/google-chrome.list:1 and /etc/apt/sources.list.d/google-chrome.list:2
W: Target Packages (main/binary-all/Packages) is configured multiple times in /etc/apt/sources.list.d/google-chrome.list:1 and /etc/apt/sources.list.d/google-chrome.list:2
W: Target Translations (main/i18n/Translation-en_IN) is configured multiple times in /etc/apt/sources.list.d/google-chrome.list:1 and /etc/apt/sources.list.d/google-chrome.list:2
W: Target Translations (main/i18n/Translation-en) is configured multiple times in /etc/apt/sources.list.d/google-chrome.list:1 and /etc/apt/sources.list.d/google-chrome.list:2
W: Target DEP-11 (main/dep11/Components-i386.yml) is configured multiple times in /etc/apt/sources.list.d/google-chrome.list:1 and /etc/apt/sources.list.d/google-chrome.list:2
W: Target DEP-11-icons (main/dep11/icons-64x64.tar) is configured multiple times in /etc/apt/sources.list.d/google-chrome.list:1 and /etc/apt/sources.list.d/google-chrome.list:2
E: Package 'virtualbox-5.1' has no installation candidate
O que está acontecendo?
siga o link abaixo. Isto irá resolver o seu problema. Eu fiz o mesmo passo ontem. Por favor, diga também a versão do sistema operacional.
sudo nano /etc/apt/sources.list
e insira abaixo da linha
deb link xenial contrib
execute o comando sudo apt-get update
abaixo do comando
sudo apt-get install linux-headers-$(uname -r) build-essential virtualbox-5.1 dkms
siga o link abaixo